[TechAssist] Re: RCA G35772AT CTC187CL DEAD/More info
- From: "Bob@Bobs tv" <woodman1@xxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 30 Sep 2004 15:06:11 -0400
Larry,
See my second post..... If I suspect that resistor I just jump a
1.5m below the chassis if that's the problem, the set will start up..That
resistor is the start up bias for the regulator....I have seen a few on the
RCA's and also on Panasonic's using same regulator...You can remove the
output transistor while you service the power supply..on the bench... in
standby at collector pad when in standby if power supply is working you will
get like 140/145Volts... Also 12V and 5V will be there...Normally if you
have problem in sweep the (-voltages) won't even be close or 0
Volts....Remember no bias to the IC no start....RCA calls that the "start"
resistor..No guaranty, but don't waste a lot of time like I did on THE FIRST
ONE...
Bob
Bobs TV Worcester, ma
woodman1@xxxxxxxx
Main 508-853-1482
Fax 508-853-1480
----- Original Message -----
From: "Larry E" <videotech@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, September 30, 2004 2:31 PM
Subject: [TechAssist] Re: RCA G35772AT CTC187CL DEAD/More info
> Bob, not sure what your saying, you want me to bridge R4104 with a 1.5
meg
> resistor?
> because pin 4 of the regulator is 0 volts? What is pin 4`s voltage
supposed to
> be? Larry E
>
> Larry Eastman
> American TV & Electronics
> Crystal River, Fl. 34428
>
> "Bob@Bobs tv" wrote:
>
> > Larry,
> > Bridge a 1.5m resistor (R4104) so you know for sure...Pin 4
needs a
> > + voltage to get the regulator going...
> > Bob,
> >
> > Bobs TV Worcester, ma
> >
> > woodman1@xxxxxxxx
> >
> > Main 508-853-1482
> > Fax 508-853-1480
> > ----- Original Message -----
> > From: "Larry E" <videotech@xxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Thursday, September 30, 2004 1:21 PM
> > Subject: [TechAssist] Re: RCA G35772AT CTC187CL DEAD/More info
> >
> > > Hi Guys, replaced the eprom and still have the same problem, zero
volts on
> > pin 6,
> > >
> > > 4.32 on pin 8&5. Unsoldered pin 54 of U1001 thinking it might have
been
> > pulling
> > > it down, no change, Q4105 is supposed to be the 5v standby source? (no
> > schematic)
> > >
> > > I have ( measured to cold ground) E= 4.77 B= 5.1 C= 11.7 volts.
Could
> > the 4.32
> > >
> > > be too low on pins 8 & 5 ? I was told pins 5&6 get the 5 volts from
pin 8
> > of
> > > U3201
> > > so I`m still confused how pin 5 can have 4.32 but pin 6 would be zero
if
> > the
> > > source
> > > is internally from pin 8 even with a new eprom installed, HELP!!!
Larry
> > E
> > >
> > > Larry Eastman
> > > American TV & Electronics
> > > Crystal River, Fl. 34428
> > >
> > > Larry E wrote:
> > >
> > > > Hi Guys, this 187CL is stone dead, no click from relay, HOT is good,
> > > > have 160 v on collector
> > > > in standby, resoldered H- driver transformer and the coil, C4107 is
> > > > good, found a bad
> > > > C4105 10uf @ 200 replaced it with no change, I need to know if the
> > > > voltages are correct
> > > > on U4101 as I don`t have the schematic, they are
> > > > Pin 1= -40
> > > > 2= -33
> > > > 4= 0
> > > > 5= .9
> > > > 6= .9
> > > > 7= .4
> > > > 8&9 = 0
> > > > 11&12 = 165 thanks in advance, Larry E
> > > > Larry Eastman
> > > > American TV & Electronics
> > > > Crystal River, Fl. 34428
> > > >
> > >
> >
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